SAP Note 20086 - INF SQL error -861: Cannot create new PDQ thread .

Symptom

INF SQL error -861: Cannot create new PDQ thread
in the online log file contains the error message:
09:16:28 User thread table overflow - user id xxxx

Cause and prerequisites

OnLine 7.10 supports Parallel Data Query (PDQ). In this case, several threads work in parallel during an SQL statement to provide the required data. SQL error 861 means that an SQL statement cannot allocate any further threads.
Onconfig parameter is not set for PDQ.

Solution
Raise the parameter USERTHREADS and the parameter TRANSACTIONS, for example:
USERTHREADS 600 # Maximum number of concurrent threads
as user informix in file $INFORMIXDIR/etc/onconfig..

You can also change the degree of parallel processing . To do this, you must change the PDQPRIORITY parameter (standard value: 50, possible value is 5, for example).

It is possible to completely switch off parallel processing of one query by setting the parameter MAX_PDQPRIORITY in the onconfig-file to 0.

Keyword: INF ONCONFIG